Evaluate first column data, set remaining columns to zero based on first column value.

I have a matrix of data, several rows, 4 columns and I want to look at the first column value and if it is above or below a certain value, set all the remaining columns in that row to zero. Sounds simple, but struggling to figure it out.

Answer 1

[Walter Roberson]

mask = YourMatrix(:,1) > TheHighCutoff | YourMatrix(:,1) < TheLowCutoff;
YourMatrix(mask,2:end) = 0;

[Andrew Paulsen]

You rock! Thanks.